如何使用msbuild下载文件？

Question

是否有内置的方式使用HTTP将文件下载到本地目录？

我可以掏出wget或编写自定义任务，但我想确保没有现成的方法来完成此任务。

在此先感谢！

Answer 1

MSBuild Community Tasks有一个任务WebDownload似乎是你所需要的。

Answer 2

除了MSBuild社区任务项目中的WebDownload任务，MSBuild扩展包（当前版本：4.x）还有一个WebClient类，可用于下载文件。您可以在这里下载的MSBuild扩展包：

• http://msbuildextensionpack.codeplex.com

下面是使用MSBuild扩展包4，下载一个文件的例子：

<Project ToolsVersion="4.0" DefaultTargets="Default" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> 
<PropertyGroup> 
    <TPath>$(MSBuildProjectDirectory)\..\MSBuild.ExtensionPack.tasks</TPath> 
    <TPath Condition="Exists('$(MSBuildProjectDirectory)\..\..\Common\MSBuild.ExtensionPack.tasks')">$(MSBuildProjectDirectory)\..\..\Common\MSBuild.ExtensionPack.tasks</TPath> 
</PropertyGroup> 
<Import Project="$(TPath)"/> 
<Target Name="Default"> 
    <!-- Download a File--> 
    <MSBuild.ExtensionPack.Web.WebClient TaskAction="DownloadFile" Url="http://hlstiw.bay.livefilestore.com/y1p7GhsJWeF4ig_Yb-8QXeA1bL0nY_MdOGaRQ3opRZS0YVvfshMfoZYe_cb1wSzPhx4nL_yidkG8Ji9msjRcTt0ew/Team%20Build%202008%20DeskSheet%202.0.pdf?download" FileName="C:\TFS Build 2008 DeskSheet.pdf"/> 
    <!-- Get the contents of a Url--> 
    <MSBuild.ExtensionPack.Web.WebClient TaskAction="OpenRead" Url="http://www.msbuildextensionpack.com"> 
     <Output TaskParameter="Data" PropertyName="Out"/> 
    </MSBuild.ExtensionPack.Web.WebClient> 
    <Message Text="$(Out)"/> 
</Target> 

由于在不同的答案中提到，WebClient似乎没有能力从安全（密码保护编辑）网络服务器。

Answer 3

如果您尝试下载需要身份验证的文件（例如TFS Web或连接到域的IIS服务器），则MSBuild扩展包和MSBuild社区任务似乎都无法提供用户名或密码到HTTP服务器。在这种情况下，我最终编写了一个自定义的MSBuild任务。这就是我所做的。

我遵循堆栈溢出用户Doug的建议，在他的回答为Download a file which requires authentication using vb.net/c#?，其中他建议一些代码添加到汤姆阿彻在代码大师网站上写的方法。

所以我用微软的Visual Studio 2010中创建下面的代码创建一个名为Wget的一个MSBuild目标一个新的C＃项目（显示完整的源代码）：

// Include references to the following frameworks in your solution: 
// - Microsoft.Build.Framework 
// - Microsoft.Build.Utilities.v4.0 
// - System 
// - System.Net 

using System; 
using System.Net; 
using System.IO; 

using Microsoft.Build.Framework; 
using Microsoft.Build.Utilities; 

namespace Wget 
{ 
    public class Wget: Task 
    { 
     [Required] 
     public String Address // HTTP address to access 
     { get; set; } 

     [Required] 
     public String LocalFilename // Local file to which the downloaded page will be saved 
     { get; set; } 

     public String Username // Credential for HTTP authentication 
     { get; set; } 

     public String Password // Credential for HTTP authentication 
     { get; set; } 

     public override bool Execute() 
     { 
      int read = DownloadFile(Address, LocalFilename, Username, Password); 

      Console.WriteLine("{0} bytes written", read); 

      return true; 
     } 

     public static int DownloadFile(String remoteFilename, String localFilename, String httpUsername, String httpPassword) 
     { 
      // Function will return the number of bytes processed 
      // to the caller. Initialize to 0 here. 
      int bytesProcessed = 0; 

      // Assign values to these objects here so that they can 
      // be referenced in the finally block 
      Stream remoteStream = null; 
      Stream localStream = null; 
      WebResponse response = null; 

      // Use a try/catch/finally block as both the WebRequest and Stream 
      // classes throw exceptions upon error 
      try 
      { 
       // Create a request for the specified remote file name 
       WebRequest request = WebRequest.Create(remoteFilename); 
       if (request != null) 
       { 
        // If a username or password have been given, use them 
        if (httpUsername.Length > 0 || httpPassword.Length > 0) 
        { 
         string username = httpUsername; 
         string password = httpPassword; 
         request.Credentials = new System.Net.NetworkCredential(username, password); 
        } 

        // Send the request to the server and retrieve the 
        // WebResponse object 
        response = request.GetResponse(); 
        if (response != null) 
        { 
         // Once the WebResponse object has been retrieved, 
         // get the stream object associated with the response's data 
         remoteStream = response.GetResponseStream(); 

         // Create the local file 
         localStream = File.Create(localFilename); 

         // Allocate a 1k buffer 
         byte[] buffer = new byte[1024]; 
         int bytesRead; 

         // Simple do/while loop to read from stream until 
         // no bytes are returned 
         do 
         { 
          // Read data (up to 1k) from the stream 
          bytesRead = remoteStream.Read(buffer, 0, buffer.Length); 

          // Write the data to the local file 
          localStream.Write(buffer, 0, bytesRead); 

          // Increment total bytes processed 
          bytesProcessed += bytesRead; 
         } while (bytesRead > 0); 
        } 
       } 
      } 
      catch (Exception e) 
      { 
       Console.WriteLine(e.Message); 
      } 
      finally 
      { 
       // Close the response and streams objects here 
       // to make sure they're closed even if an exception 
       // is thrown at some point 
       if (response != null) response.Close(); 
       if (remoteStream != null) remoteStream.Close(); 
       if (localStream != null) localStream.Close(); 
      } 

      // Return total bytes processed to caller. 
      return bytesProcessed; 
     } 
    } 
} 

随着到位，我可以添加以下任务到我的MSBuild项目：

<!-- Get the contents of a Url--> 
<Wget 
    Address="http://mywebserver.com/securepage" 
    LocalFilename="mydownloadedfile.html" 
    Username="myusername" 
    Password="mypassword"> 
</Wget> 

wget的任务下载由mywebserver.com服务的页面，并将其保存到当前工作目录mydownloadedfile.html文件，使用用户名“名为myusername”和密码“我的密码”。

但是，为了使用自定义Wget MSBuild任务，我必须告诉MSBuild在哪里可以找到Wget程序集文件（.dll）。这是用的MSBuild的元素来完成的：

<!-- Import your custom MSBuild task --> 
<UsingTask AssemblyFile="MyCustomMSBuildTasks\Wget\bin\Release\Wget.dll" TaskName="Wget" /> 

如果你想获得幻想，你甚至可以有你的MSBuild项目建设Wget的，它被称为前。要做到这一点，建立与<MSBuild Projects>任务的解决方案，并与<UsingTaks AssemblyFile>任务导入，这样的事情：

<!-- Build the custom MSBuild target solution--> 
<MSBuild Projects="MyCustomMSBuildTasks\CustomBuildTasks.sln" Properties="Configuration=Release" /> 

<!-- Import your custom MSBuild task --> 
<UsingTask AssemblyFile="MyCustomMSBuildTasks\Wget\bin\Release\Wget.dll" TaskName="Wget" /> 

<!-- Get the contents of a Url--> 
<Wget 
    Address="http://mywebserver.com/securepage" 
    LocalFilename="mydownloadedfile.html" 
    Username="myusername" 
    Password="mypassword"> 
</Wget> 

如果你从来没有之前创建一个自定义的MSBuild目标，这不是太困难的 - 一次你知道基础知识。看看上面的C＃代码，看看官方的MSDN文档，并在网上搜索更多的例子。一个良好的开始是：

• http://msdn.microsoft.com/en-us/library/t9883dzc.aspx

Answer 4

在MSBuild的4.0，你可以使用内联任务，以避免需要编译和在单独的程序部署自定义任务。

<UsingTask TaskName="DownloadFile" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll"> 
    <ParameterGroup> 
     <Address ParameterType="System.String" Required="true"/> 
     <FileName ParameterType="System.String" Required="true" /> 
    </ParameterGroup> 
    <Task> 
     <Reference Include="System" /> 
     <Code Type="Fragment" Language="cs"> 
     <![CDATA[ 
      new System.Net.WebClient().DownloadFile(Address, FileName); 
     ]]> 
     </Code> 
    </Task> 
    </UsingTask> 

    <Target Name="DownloadSomething"> 
    <DownloadFile Address="http://somewebsite/remotefile" FileName="localfilepath" /> 
    </Target>